A class of machines exists in the art generally known as “scroll” machines for the displacement of various types of fluids. Such machines may be configured as an expander, a displacement engine, a pump, a compressor, etc., and the features of the present invention are applicable to any one of these machines. For purposes of illustration, however, the disclosed embodiments are in the form of a hermetic refrigerant compressor.
Generally speaking, a scroll machine comprises two spiral scroll wraps of similar configuration, each mounted on a separate end plate to define a scroll member. The two scroll members are interfitted together with one of the scroll wraps being rotationally displaced 180° from the other. The machine operates by orbiting one scroll member (the “orbiting scroll”) with respect to the other scroll member (the “fixed scroll” or “non-orbiting scroll”) to make moving line contacts between the flanks of the respective wraps, defining moving isolated crescent-shaped pockets of fluid. The spirals are commonly formed as involutes of a circle, and ideally there is no relative rotation between the scroll members during operation; i.e., the motion is purely curvilinear translation (i.e., no rotation of any line in the body). The fluid pockets carry the fluid to be handled from a first zone in the scroll machine where a fluid inlet is provided, to a second zone in the machine where a fluid outlet is provided. The volume of a sealed pocket changes as it moves from the first zone to the second zone. At any one instant in time there will be at least one pair of sealed pockets; and where there are several pairs of sealed pockets at one time, each pair will have different volumes. In a compressor, the second zone is at a higher pressure than the first zone and is physically located centrally in the machine, the first zone being located at the outer periphery of the machine.
A compressor may include a shell assembly, a first scroll member, and a second scroll member. The first scroll member may be located within the shell assembly and may include a first end plate and a first spiral wrap extending from a first side of the first end plate. The first end plate may define an oil groove extending into the first side. The second scroll member may be located within the shell assembly and supported for orbital movement relative to the first scroll member. The second scroll member may include a second end plate and a second spiral wrap extending from the second end plate and meshingly engaged with the first spiral wrap to form compression pockets.
The first scroll member may be axially fixed relative to the shell assembly. The first end plate and the shell assembly may cooperate to define a chamber receiving a pressurized fluid to deflect the first end plate and the first spiral wrap toward the second scroll member. The first end plate may define an auxiliary passage in fluid communication with an intermediate one of the compression pockets and the chamber to provide the pressurized fluid to the chamber. The first scroll member may define a discharge passage and the chamber may be isolated from the discharge passage.
The oil groove may be in communication with a pressurized oil source. The compressor may additionally include a control valve located in a supply path of oil to the oil groove. The compressor may additionally include an oil sump in communication with the oil groove.
The shell assembly may define an oil sump. The oil groove may be an annular groove. The oil groove may lubricate an interface between the first scroll member and the second scroll member. The compressor may further include an oil separator in communication with a discharge passage defined in the first scroll member. The oil separator may receive a mixture of oil and compressed gas from the discharge passage and may return the oil to the compressor. The compressor may further include a control valve in communication with the oil separator and controlling the flow of oil returned into the compressor from the oil separator. The oil separator may be located external to the shell assembly and the control valve may control the flow of oil from the oil separator to the shell assembly.
In another arrangement a compressor may include a shell assembly, a non-orbiting scroll member and an orbiting scroll member. The non-orbiting scroll member may be located within the shell assembly and may include a first end plate and a first spiral wrap extending from a first side of the first end plate. The first end plate may define an oil groove extending into the first side. The orbiting scroll member may be located within the shell assembly and may include a second end plate and a second spiral wrap extending from the second end plate and meshingly engaged with the first spiral wrap to form compression pockets. The non-orbiting scroll member may be axially fixed relative to the shell assembly. The compressor may further include an oil separator in communication with a discharge passage defined in the non-orbiting scroll member. The oil separator may receive a mixture of oil and compressed gas from the discharge passage and may return the oil to the compressor. The compressor may further include a control valve in communication with the oil separator and controlling an oil flow returned to the compressor from the oil separator.
In another arrangement, a compressor may include a shell assembly, a non-orbiting scroll member, an orbiting scroll member, and an oil separator. The shell assembly may define an oil sump. The non-orbiting scroll member may be located within and axially fixed relative to the shell assembly. The non-orbiting scroll member may include a first end plate and a first spiral wrap extending from a first side of the first end plate. The first end plate may define a discharge passage and an oil groove extending into the first side. The orbiting scroll member may be located within the shell assembly and may include a second end plate and a second spiral wrap extending from the second end plate and meshingly engaged with the first spiral wrap to form compression pockets. The oil separator may be in communication with the discharge passage defined in the non-orbiting scroll member and may receive a mixture of oil and compressed gas from the discharge passage and may return the oil to the compressor. The oil groove may be in communication with the pressurized oil source.